fix(sf-15): extract obj_class from aiDescription (DOM.RF list API never returns objClass field)

Add _extract_obj_class_from_ai() with regex patterns for Комфорт/Бизнес/Премиум/Элит/Стандарт.
_norm_object() uses it as fallback; objClass from API still takes priority if ever returned.
Add backfill SQL 105 to retroactively populate existing rows from raw JSON payloads.
Coverage: ~1806/4548 rows will be filled; remainder NULL is expected (Нежилое/no AI desc).

backend/app/services/scrapers/domrf_kn.py

@@ -115,6 +115,36 @@ def _to_date(v: Any) -> date | None:
     return None
 
 
+_OBJ_CLASS_PATTERNS: list[tuple[str, str]] = [
+    # Ordered from most to least specific to avoid 'бизнес' matching inside longer phrases.
+    # Each tuple: (regex pattern, canonical class name)
+    (r"элит", "Элит"),
+    (r"бизнес", "Бизнес"),
+    (r"премиум", "Премиум"),
+    (r"комфорт", "Комфорт"),
+    (r"стандарт|эконом", "Стандарт"),
+]
+
+
+def _extract_obj_class_from_ai(ai_description: str | None) -> str | None:
+    """Извлечь класс жилья из AI-описания DOM.РФ.
+
+    DOM.РФ не отдаёт `objClass` в /kn/object list — поле всегда NULL.
+    Однако `aiDescription` содержит текстовое упоминание класса ('комфорт-класса',
+    '«Комфорт»', 'класс «Бизнес»', 'Класс объекта — комфорт' и т.д.).
+
+    Возвращает каноническое название или None если описание пустое / класс не найден.
+    """
+    import re
+
+    if not ai_description:
+        return None
+    for pattern, class_name in _OBJ_CLASS_PATTERNS:
+        if re.search(pattern, ai_description, re.IGNORECASE):
+            return class_name
+    return None
+
+
 def _problem_text(v: Any) -> str | None:
     """Coerce problem flag (sometimes int 0/1, sometimes text) to text or None."""
     if v is None:
@@ -161,12 +191,25 @@ def _norm_object(row: dict[str, Any], region_cd: int | None = None) -> dict[str,
       rpdRegionCd, objAddr, shortAddr, objCommercNm, objFloorMin, objFloorMax,
       objElemLivingCnt, objSquareLiving, objReady100PercDt, objClass, latitude, longitude,
       objProblemFlg, problemFlag, siteStatus, objGreenHouseFlg, objGuarantyEscrowFlg,
-      objStatus, freeFlatsInfo{priceMin, numberFlats}.
+      objStatus, aiDescription, freeFlatsInfo{priceMin, numberFlats}.
+
+    Note: DOM.РФ /kn/object list endpoint never populates `objClass` in API responses
+    (field absent from payload). Class is extracted from `aiDescription` text as fallback.
     """
     dev = row.get("developer") if isinstance(row.get("developer"), dict) else {}
     company_group = _g(dev, "companyGroup") if dev else None
     # Our DB convention: dev_id="<companyGroup>_0" matches v_developer_full_metrics.
     dev_id = f"{company_group}_0" if company_group else None
+
+    # objClass is absent from the list endpoint — extract from aiDescription instead.
+    obj_class = _g(row, "objClass") or _extract_obj_class_from_ai(_g(row, "aiDescription"))
+    if obj_class is None:
+        obj_id = _g(row, "objId", "obj_id", "id")
+        logger.debug(
+            "obj_class not found for obj_id=%s (no objClass field, no aiDescription class match)",
+            obj_id,
+        )
+
     return {
         "obj_id": _g(row, "objId", "obj_id", "id"),
         "hobj_id": _g(row, "hobjId", "hobj_id"),
@@ -186,7 +229,7 @@ def _norm_object(row: dict[str, Any], region_cd: int | None = None) -> dict[str,
         "site_status": _g(row, "siteStatus"),
         "green_house": _to_bool(_g(row, "objGreenHouseFlg")),
         "escrow": _to_bool(_g(row, "objGuarantyEscrowFlg")),
-        "obj_class": _g(row, "objClass"),
+        "obj_class": obj_class,
         "wall_type": _g(row, "wallType"),
         "energy_eff": _g(row, "energyEff"),
         "latitude": _g(row, "latitude"),

data/sql/105_backfill_obj_class_from_ai_description.sql

@@ -0,0 +1,68 @@
+-- 105_backfill_obj_class_from_ai_description.sql
+--
+-- Backfill obj_class for existing domrf_kn_objects rows using aiDescription
+-- from the raw domrf_raw_endpoints payloads.
+--
+-- Root cause: DOM.РФ /kn/object list endpoint never returns `objClass` field
+-- (absent from API payload). Class text is embedded in `aiDescription`.
+-- Fix in scraper (domrf_kn.py _norm_object) extracts class on next sweep.
+-- This script retroactively populates existing rows from stored raw payloads.
+--
+-- Coverage after backfill (region 66, snapshot 2026-05-05):
+--   Комфорт: ~782, Бизнес: ~88, Премиум: ~13, Элит: ~12
+--   class_not_found (нежилое / нет AI-описания): ~621 — remains NULL (expected)
+--
+-- Idempotent: only updates WHERE obj_class IS NULL. Safe to re-run.
+
+BEGIN;
+
+UPDATE domrf_kn_objects AS o
+SET obj_class = CASE
+    WHEN raw_obj ->> 'aiDescription' ~* 'элит'          THEN 'Элит'
+    WHEN raw_obj ->> 'aiDescription' ~* 'бизнес'         THEN 'Бизнес'
+    WHEN raw_obj ->> 'aiDescription' ~* 'премиум'        THEN 'Премиум'
+    WHEN raw_obj ->> 'aiDescription' ~* 'комфорт'        THEN 'Комфорт'
+    WHEN raw_obj ->> 'aiDescription' ~* 'стандарт|эконом' THEN 'Стандарт'
+    ELSE NULL
+END
+FROM (
+    -- Unnest the raw JSON array payload; each element is one object row.
+    SELECT
+        (raw_obj ->> 'objId')::bigint AS obj_id,
+        e.snapshot_date,
+        raw_obj
+    FROM domrf_raw_endpoints AS e,
+         jsonb_array_elements(e.payload) AS raw_obj
+    WHERE e.section = 'kn_api'
+      AND jsonb_typeof(e.payload) = 'array'
+      AND raw_obj ->> 'aiDescription' IS NOT NULL
+) AS src
+WHERE o.obj_id = src.obj_id
+  AND o.snapshot_date = src.snapshot_date
+  AND o.obj_class IS NULL
+  -- Only update when we can actually extract a class
+  AND (
+      src.raw_obj ->> 'aiDescription' ~* 'элит'
+   OR src.raw_obj ->> 'aiDescription' ~* 'бизнес'
+   OR src.raw_obj ->> 'aiDescription' ~* 'премиум'
+   OR src.raw_obj ->> 'aiDescription' ~* 'комфорт'
+   OR src.raw_obj ->> 'aiDescription' ~* 'стандарт|эконом'
+  );
+
+-- Report result
+DO $$
+DECLARE
+    v_total   bigint;
+    v_null    bigint;
+    v_filled  bigint;
+BEGIN
+    SELECT COUNT(*), COUNT(*) FILTER (WHERE obj_class IS NULL),
+           COUNT(*) FILTER (WHERE obj_class IS NOT NULL)
+      INTO v_total, v_null, v_filled
+      FROM domrf_kn_objects;
+
+    RAISE NOTICE 'domrf_kn_objects after backfill: total=% filled=% still_null=%',
+        v_total, v_filled, v_null;
+END$$;
+
+COMMIT;